Inhibition of α-glucosidase and α-amylase by herbal compounds for the treatment of type 2 diabetes : a validation of in silico reverse docking with in vitro enzyme assays

BACKGROUND : α-Amylase and α-glucosidase are important therapeutic targets for the management of type 2 diabetes mellitus. The inhibition of these enzymes decreases postprandial hyperglycemia. In the present study, compounds found in commercially available herbs and spices were tested for their ability to inhibit α-amylase and α-glucosidase. These compounds were acetyleugenol, apigenin, cinnamic acid, eriodictyol, myrcene, piperine, and rosmarinic acid. METHODS : The enzyme inhibitory nature of the compounds was evaluated using in silico docking analysis with Maestro software and was further confirmed by in vitro α-amylase and α-glucosidase biochemical assays. RESULTS : The relationships between the in silico and in vitro results were well correlated; a more negative docking score was associated with a higher in vitro inhibitory activity. There was no significant (P > .05) difference between the inhibition constant (Ki) value of acarbose, a widely prescribed α-glucosidase and α-amylase inhibitor, and those of apigenin, eriodictyol, and piperine. For α-amylase, there was no significant (P > .05) difference between the Ki value of acarbose and those of apigenin, cinnamic acid, and rosmarinic acid. The effect of the herbal compounds on cell viability was assessed with the sulforhodamine B (SRB) assay in C2C12 and HepG2 cells. Acetyleugenol, cinnamic acid, myrcene, piperine, and rosmarinic acid had similar (P > .05) IC50 values to acarbose. CONCLUSIONS : Several of the herbal compounds studied could regulate postprandial hyperglycemia. Using herbal plants has several advantages including low cost, natural origin, and easy cultivation. These compounds can easily be consumed as teas or as herbs and spices to flavor food.SUPPLEMENTARY MATERIAL : Figure S1 Lineweaver-Burk graphs of the inhibition of α-amylase by herbal compounds (n = 3, SD error bars). Figure S2. Lineweaver-Burk graphs of the inhibition of α-glucosidase by herbal compounds (n = 3, SD error bars). Figure S3. Viability of C2C12 cells after 72 hours exposure to acarbose (control) and herbal compounds (n = 3, SD error bars). Figure S4. Viability of HepG2 cells after 72 hours exposure to acarbose (control) and herbal compounds (n = 3, SD error bars). Table S1. Michaelis-Menten parameters for the inhibition of α-amylase by herbal compounds. Table S2. Michaelis-Menten parameters for the inhibition of α-glucosidase by herbal compounds.The University of Pretoria with a postgraduate scholarship.http://wileyonlinelibrary.com/journal/jdbhj2022AnatomyBiochemistryGeneticsMicrobiology and Plant Patholog

Headspace volatiles of the edible fruit pulp of Parinari curatellifolia growing in Malawi using solid phase microextraction

Head-space volatiles of the edible pulp of the mobola plum (Parinari curatellifolia) were extracted using solid phase microextraction (SPME), and their identities determined by GC–FID and GC–MS systems. The SPME method extracted eleven major compounds accounting for 99.0% of the volatile constituents. The volatiles were ethyl butyrate, 28.7%; ethyl isovalerate, 19.3%; ethyl valerate, 12.4%; ethyl hexanoate, 3.7%; ethyl benzoate, 2.5%; isoamyl isovalerate, 0.3%; phenol, 10.5%;α-bergamotene, 1.1%; β-farnesene, 3.0%; 2,6-diterbutyl-4-methylphenol, 3.1% and phenylacetonitrile, 14.4%. Thus, the valerate and butyrate esters are themost abundant volatiles in the head-space of the edible pulp of the ripe fruit using the SPME method. The compounds, ethyl isovalerate, ethyl valerate, isoamyl isovalerate, phenol, 2,6-diterbutyl-4-methyl-phenol, phenylacetonitrile, α-bergamotene and β-farnesene were identified for the first time in the head-space of this fruit.The Carnegie Regional Initiative in Science Education (Carnegie-RISE) through the Southern Africa Biochemistry and Informatics for Natural Products (SABINA) network for funding and a fellowship to Tinotenda Shoko and the ACP EU through the POL-SABINA network for a study attachment at the University of Pretoria.http://www.elsevier.com/locate/sajbhb201

Bud development, flowering and fruit set of Moringa oleifera Lam. (Horseradish Tree) as affected by various irrigation levels

Moringa oleifera is becoming increasingly popular as an industrial crop due to its multitude of useful attributes as water purifier, nutritional supplement and biofuel feedstock. Given its tolerance to sub-optimal growing conditions, most of the current and anticipated cultivation areas are in medium to low rainfall areas. This study aimed to assess the effect of various irrigation levels on floral initiation, flowering and fruit set. Three treatments namely, a 900 mm (900IT), 600 mm (600IT) and 300 mm (300IT) per annum irrigation treatment were administered through drip irrigation, simulating three total annual rainfall amounts. Individual inflorescences from each treatment were tagged during floral initiation and monitored throughout until fruit set. Flower bud initiation was highest at the 300IT and lowest at the 900IT for two consecutive growing seasons. Fruit set on the other hand, decreased with the decrease in irrigation treatment. Floral abortion, reduced pollen viability as well as moisture stress in the style were contributing factors to the reduction in fruiting/yield observed at the 300IT. Moderate water stress prior to floral initiation could stimulate flower initiation, however, this should be followed by sufficient irrigation to ensure good pollination, fruit set and yield

Exploring the anti-proliferative activity of Pelargonium sidoides DC with in silico target identification and network pharmacology

Pelargonium sidoides DC (Geraniaceae) is a medicinal plant indigenous to Southern Africa that has been widely evaluated for its use in the treatment of upper respiratory tract infections. In recent studies, the anti-proliferative potential of P. sidoides was shown, and several phenolic compounds were identified as the bioactive compounds. Little, however, is known regarding their anti-proliferative protein targets. In this study, the anti-proliferative mechanisms of P. sidoides through in silico target identification and network pharmacology methodologies were evaluated. The protein targets of the 12 phenolic compounds were identified using the target identification server PharmMapper and the server for predicting Drug Repositioning and Adverse Reactions via the Chemical–Protein Interactome (DRAR-CPI). Protein–protein and protein–pathway interaction networks were subsequently constructed with Cytoscape 3.4.0 to evaluate potential mechanisms of action. A total of 142 potential human target proteins were identified with the in silico target identification servers, and 90 of these were found to be related to cancer. The protein interaction network was constructed from 86 proteins involved in 209 interactions with each other, and two protein clusters were observed. A pathway enrichment analysis identified over 80 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enriched with the protein targets and included several pathways specifically related to cancer as well as various signaling pathways that have been found to be dysregulated in cancer. These results indicate that the anti-proliferative activity of P. sidoides may be multifactorial and arises from the collective regulation of several interconnected cell signaling pathways.https://link.springer.com/journal/110302018-11-18hj2017AnatomyBiochemistr

Volatile constituents of fruit pulp of Strychnos cocculoides (Baker) growing in Malawi using solid phase microextraction

Volatile constituents of the edible pulp of Strychnos cocculoides (Monkey orange) were extracted using solid phase microextraction (SPME) and their identity established by GC–FID and GC–MS systems. Six compounds were extracted and identified: isobutyl acetate, 53.2%; 2-methylbutyl acetate, 12.8%; ethyl-2-methylbutyrate, 10.5%; 2, 6-ditetrabutyl-4-methyl-phenol, 8.4%; butyl-2-methyl butyrate, 6.7% and geranyl acetate, 3.1%. These accounted for 94.7% of the volatile constituents in the pulp. Thus, the acetate and butyrate esters were the most abundant volatiles in the edible pulp of the ripe fruit.Carnegie Regional Initiative in Science Education (Carnegie-RISE) through the Southern Africa Biochemistry and Informatics for Natural Products (SABINA) network and the ACP EU through the POL-SABINA network. Open Access funded by SAAB.http://www.elsevier.com/locate/sajbhb2016Biochemistr

Screening of candidate bioactive secondary plant metabolite Ion-features from Moringa oleifera accessions associated with high and low enteric methane inhibition from ruminants

DATA AVAILABILITY STATEMENT : Data will be stored in the University of Pretoria repository, and access to the data will be granted by making a reasonable request to the University of Pretoria or the corresponding author.This study evaluated the relationship of secondary bioactive plant metabolite ion-features (MIFs) of Moringa oleifera accessions with antimethanogenesis to identify potential MIFs that were responsible for high and low methane inhibition from ruminants. Plant extracts from 12 Moringa accessions were evaluated at a 50 mg/kg DM feed for gas production and methane inhibition. Subsequently, the accessions were classified into low and high enteric methane inhibition groups. Four of twelve accessions (two the lowest and two the highest methane inhibitors), were used to characterize them in terms of MIFs. A total of 24 samples (12 from lower and 12 from higher methane inhibitors) were selected according to their methane inhibition potential, which ranged from 18% to 29%. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and untargeted metabolomics with univariate and multivariate statistical analysis with MetaboAnalyst were used in the study. Although 86 MIFs showed (p < 0.05) variation between higher and lower methane inhibition groups and lay within the detection ranges of the UPLC-MS column, only 14 were significant with the volcano plot. However, Bonferroni correction reduced the candidate MIFs to 10, and their R2-value with methane production ranged from 0.39 to 0.64. Eventually, MIFs 4.44_609.1462 and MIF 4.53_433.1112 were identified as bioactive MIFs associated with higher methane inhibition, whereas MIF 9.06_443.2317 and 15.00_487.2319 were associated with lower methane inhibition with no significant effect on in vitro organic matter digestibility of the feed. These MIFs could be used by plant breeders as potential markers to develop new M. oleifera varieties with high methane inhibition characteristics. However, further investigation on identifying the name, structure, and detailed biological activities of these bioactive metabolites needs to be carried out for future standardization, commercialization, and application as dietary methane mitigation additives.The National Research Foundation (NRF) of South Africa.https://www.mdpi.com/journal/metabolitesam2023Animal and Wildlife SciencesBiochemistryGeneticsMicrobiology and Plant Patholog

Relationships between agronomic traits of Moringa accessions and In vitro gas production characteristics of a test feed Incubated with or without moringa plant leaf extracts

The use of medicinal plants and their extracts has recently attracted the attention of many researchers as a methane (CH4 ) mitigation strategy. This study evaluated the relationship of agronomic traits of Moringa accessions with in vitro gas production measurements and feed digestibility from ruminants. Twelve Moringa accessions were grown at the Roodeplaat experimental site of the Agricultural Research Council in Pretoria, South Africa. Agronomic traits, such as seedling survival rate, leaf yield, canopy and stem diameter, plant height, number of primary branches, plant vigor, greenness, chlorosis, disease and pest incidences were recorded. The leaves were harvested in the fifth month after transplanting to the field. Freeze-dried leaves were extracted with methanol, and their total phenolic and total flavonoid contents were determined. The extract was applied at a dose of 50 mg/kg of dry matter (DM) feed for in vitro gas production studies. Most of the growth and agronomic traits, i.e., seedling survival rate, leaf yield, canopy diameter, plant height, number of primary branches, the score of plant vigor, and greenness, total phenolics and flavonoids were significantly different among the accessions except for stem diameter and chlorosis score. All accession leaf extracts significantly reduced the total gas and CH4 production compared with the control with equal or higher in vitro organic matter digestibility. Higher CH4 inhibition was obtained in Moringa oleifera (M. oleifera) A3 (28.4%) and A11 (29.1%), whereas a lower inhibition was recorded in A1 (17.9%) and A2 (18.2%). The total phenolic (0.62) and total flavonoid (0.71) contents as well as most agronomic traits of the accessions were positively correlated with the CH4 inhibition potential of the accessions. Moringa oleifera accessions A3, A8 and A11 resulted in higher in vitro CH4 inhibition potential and improved organic matter digestibility of the feed with equal or higher adaptability performances in the field. Thus, there is a possibility of selecting Moringa accessions for higher antimethanogenic activity without compromising the feed digestibility by selecting for higher total phenolics, total flavonoids and agronomic performances traits. There is a need for further study to determine the long-term adaptability of promising accessions in the study area with concurrent antimethanogenesis efficacy when used in the diet of ruminant animals.The National Research Foundation (NRF) of South Africa.https://www.mdpi.com/journal/plantsdm2022Animal and Wildlife SciencesBiochemistryGeneticsMicrobiology and Plant Patholog

Anti-proliferative properties of commercial Pelargonium sidoides tincture, with cell-cycle G(0)/G(1) arrest and apoptosis in Jurkat leukaemia cells

CONTEXT : Pelargonium sidoides DC (Geraniaceae) is an important medicinal plant indigenous to South Africa and Lesotho. Previous studies have shown root extracts rich in polyphenolic compounds with antibacterial, antiviral and immunomodulatory activities. Little is known regarding the anticancer properties of Pelargonium sidoides extracts. OBJECTIVE : This study evaluates the anti-proliferative effects of a Pelargonium sidoides radix mother tincture (PST). MATERIALS AND METHODS : The PST was characterized by LC-MS/MS. Anti-proliferative activity was evaluated in the pre-screen panel of the National Cancer Institute (NCI-H460, MCF-7 and SF-268) and the Jurkat leukemia cell line at concentrations of 0-150 μg/mL. Effect on cell growth was determined with sulforhodamine B and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays after 72 h. Effect on cell cycle and apoptosis induction in Jurkat cells was determined by flow cytometry with propidium iodide and Annexin V: fluorescein isothiocyanate staining. RESULTS : Dihydroxycoumarin sulfates, gallic acid as well as gallocatechin dimers and trimers were characterized in PST by mass spectrometry. Moderate anti-proliferative effects with GI50 values between 40 and 80 μg/mL observed in the NCI-pre-screen panel. Strong activity observed with Jurkat cells with a GI50 of 6.2 μg/mL, significantly better than positive control 5-fluorouracil (GI50 of 9.7 μg/mL). The PST arrested Jurkat cells at G0/G1 phase of the cell cycle and increased the apoptotic cells from 9% to 21%, while the dead cells increased from 4% to 17%. CONCLUSION : We present evidence that Pelargonium sidoides has cancer cell type specific antiproliferative effects and may be a source of novel anticancer molecules.National Research Foundation of South Africa.http://www.tandfonline.com/loi/iphb202017-09-30hb2016AnatomyBiochemistr

Assessment of genome-wide DArT-seq markers for tea Camellia sinensis (L.) O. Kuntze germplasm analysis

Tea is the world’s most consumed beverage, next to water. This makes it an economically important crop. However, the genetic relationship between the cultivars at the Tea Research Foundation of Central Africa (TRFCA) have not been classified. This study assessed 56 tea accessions from the TRFCA. The 56 accessions were split into five groups, namely, Cambod type, China type, TRFCA, Tea Research Institute (TRI), and unknown. A total of 16,382 genome-wide genetic markers were developed using a next-generation sequencing (NGS) platform at Diversity Array Technology (DArT). The current study also explored the usefulness of the DArT-seq markers for tea germplasm analysis. The genetic relationships amongst the cultivars were analysed using the neighbour-joining method and UPGMA; this was successful in clustering the different cultivars into groups of origin. Principal coordinate analysis (PCoA) showed that 33 TRFCA-derived cultivars were distributed in all four quadrants. Analysis of molecular variance (AMOVA) revealed that there was a higher proportion of genetic variation (94%) within the groups than there was amongst the groups (6%). Nei’s unbiased genetic distances amongst groups suggested that the 33 TRFCA-derived cultivars had a low genetic distance from the other four groups. This confirms the PCoA inference that the 33 TRFCA had a high genetic admixture. The genetic structure was utilised to assign three cultivars of unknown origin, to the Cambod-type group. Two cultivars were closely related to the China-type group. Our findings are a useful guide for future tea breeding programmes in Southern Africa.The Carnegie Regional Initiative in Science and Education (Carnegie-RISE) through the Southern African Biochemistry and Informatics for Natural Products (SABINA) network. and the National Research Foundation (NRF).http://link.springer.com/journal/11295hj2020BiochemistryGeneticsMicrobiology and Plant Patholog

SWAPDT : a method for short-time withering assessment of probability for drought tolerance in Camellia sinensis validated by targeted metabolomics

Climate change is causing droughts affecting crop production on a global scale. Classical breeding and selection strategies for drought-tolerant cultivars will help prevent crop losses. Plant breeders, for all crops, need a simple and reliable method to identify drought-tolerant cultivars, but such a method is missing. Plant metabolism is often disrupted by abiotic stress conditions. To survive drought, plants reconfigure their metabolic pathways. Studies have documented the importance of metabolic regulation, i.e. osmolyte accumulation such as polyols and sugars (mannitol, sorbitol); amino acids (proline) during drought. This study identified and quantified metabolites in drought tolerant and drought susceptible Camellia sinensis cultivars under wet and drought stress conditions. For analyses, GC-MS and LC-MS were employed for metabolomics analysis. %RWC results show how the two drought tolerant and two drought susceptible cultivars differed significantly (p ≤ 0.05) from one another; the drought susceptible exhibited rapid water loss compared to the drought tolerant. There was a significant variation (p < 0.05) in metabolite content (amino acid, sugars) between drought tolerant and drought susceptible tea cultivars after short-time withering conditions. These metabolite changes were similar to those seen in other plant species under drought conditions, thus validating this method. The Short-time Withering Assessment of Probability for Drought Tolerance (SWAPDT) method presented here provides an easy method to identify drought tolerant tea cultivars that will mitigate the effects of drought due to climate change on crop losses.The financial support to conduct this research, and study grants for CN and RK from James Finlay (Kenya) Ltd, George Williamson (Kenya) Ltd, Sotik Tea Company (Kenya) Ltd, Mcleod Russell (Uganda) Ltd, and the Tea Research Institute of Kenya. The C. sinensis cultivars used in this study were provided by the Tea Research Foundation of Central Africa (Malawi) and the Tea Research Institute of Kenya. Supplementary funding was provided by, the Technology and Human Resources for Industry Programme (THRIP), an initiative of the Department of Trade and Industries of South Africa (dti), the National Research Foundation (NRF) of South Africa, and the University of Pretoria (South Africa).http://www.elsevier.com/locate/jplph2017-07-31hb2016BiochemistryStatistic